Flexible corrugated-metal wall for collapsible and expansible vessels.



. M. FULTON.

Patented Deo. 2'?, 1910.

vwentoz W FLEXIBLE GORRUGATED METAL WALL POR UOLLAPSIBLB AND EXPANSIBLB VESSELS `APPLIGATION FILED MAY 5, 1909.

WESTON M." FULTON, OFKNOXVILLE, TENNESSEE.

FIBLE CORRUG'ATED-METAL WALL FOR COLLAPSIBLE .AND EXPANSIBLE YESSELS.

Specication of Letters Patent. Patented D963. 2'?, i919.

Apjgblication-viled May 5, 1909. eria1 No. 494,202. F

its object to provide a flexible and durable wall capable of withstanding heavy pressures such as occur in vessels of this class when confining steam or water under pressure. i

Heretofore in constructing the walls of collapsible and expansible vessels which are required to withstand heavy fluid pressure, it has been the practice to use a single thickness of sheet metal of such thickness as is requisite to afford the necessary strength to resist the pressure of the conned fluid. Certain disadvantages result from the use of such thick sheet met-al in walls of collapsible and expansible vessels. Among these disadvantages maybe mentioneddiminished resiliency in the Walls whereby f sensitiveness to fluctuation of Huid pressure is sacriced; increased tendency of the thick walls to crack at the bends, due to increased strains in the outer and inner layers at these points; and greater tendency of the vessel to leak along theseam because of its increased thickness. The presence of a thicker seam in the wallsv of the vessel also accentuates the difference in resiliency between' the seam and other portions'of the wall, and this is undesirable.

A brief consideration of some of the properties of corrugated sheet metal and some ofy the mechanical principles applicable -thereto will assist in the understanding of ble vessels, however,

the present improvement.

It is a Wellknown fact that when metal, such as used for the construction of flexible walls of collapsible and vexpansible vessels, is rolled into thin sheets, its tensile strength becomes considerably greater in proportioncto `its thickness as the she'et is thinned down; This fact I.

makes it desirable to use as thin sheets of metal as practicable for the walls `of such vessels. In certain collapsible and expansii considerable strength .1s required in the walls requiring the use of thicker sheet metal, When such a sheet metal is placed under a bending strain it is found that the laments of metal along the I convex side of the bend are stretched, and those on the concave side are shortened, while along the so-called median line within the bend the laments are not subjected to strains tending to either stretch or shorten them. It is, therefore, evident that when a flexible wall provided with such bends is collapsed that all the particles of met-al on thev convex side of the median line are stretched apart while the particles of metal on the concave side ofthe same median line are upset. When the Wall is expanded a reverse set of strains is produced.

lf the wall is comparatively thick, asit is in the case of collapsible and expansible vessels under consideration, the particles around the concave and convex surfaces of the wall are subject to great strain. rlhe4 wall by repeated collapsing and expanding weakens at these points and finally breaks through.. Furthermore, with increased thickness of the wall greater force is required to overcome its resilience, and hence its flexibility will not be great. In accordance with my invention, l provide flexible walls for collapsible and extensible vessels by building them up `of a plurality of thin sheets of metal in contact with each other, directly or through the medium of a 'lubricatin p graphite, soapstone yor t e like, which-reduces friction between the layers. The several laminations of 'the wall may be of the same or of a different metal. When uids are to be coni-ined which have a corroding action on the wall of the vessel, Al prefer to make the exposed layer of metal which -is capable of resisting the action of the uid. ln case the wall confines steam or water the inner layer is preferably made of copper,

while the remaining layersof the wall are made of a cheaper metal such as steel, therematerial such as by combining strength and elasticity, while"V protecting against corrosion.

The mvention is not'coniined to anyspar-i. l;

ticular kind of'metal or number of lamina? l I laminzc. l have found, for example, foii'r.

tions, provided there is a plurality Vof such layers of sheet metal each of about .01 Iinch `thickness, suitable for the walls of collapsible i and expansible vessels designed to confine` steam or hot water under pressure. My lmproved wall may bev assembled in a variety of ways and may be made from` y l seainlesstubing, or from sheets be'nt into cylindrical forni with their edges'united by any separately bend up each of the several sheets into cylindrical forni, secure the lapped edges by braziiig, and assemble the dylinders in o a nest, each seam being displaced with respect to its neighbor so as to distribute the seams around the circumference of lthe wall. The nested cylinders are then corrugated, and the corriigations may be of any desired configuration. Instead of constructing the wall of separate sheets, it may be formed out of a single sheetfof metal bent into a spiral form with'its edges secured to the wall by brazing or otherwise.

The inventive idea involved is capable of being embodied in a variety of forms, some of which, for the purpose of illustration of the invention, aresliown in thel accompany-y ing drawings, in wliich- Figure 1 is a view in elevation and in part section of a coirugated sheet metal wall made in accordance with my invention; Fig. 2 is a plan view ofFig. 1, showing the arrangement of the lapped seams; Fig. 3 is a detailview showing a laminated wall with lubricant between the layers; Figs. 4 and are views in plan of laminated walls showing diti'erent embodiments of my improvement; and Figs. 6, 7 and 8 are diagrammatic views for the purpose of illustrating the operation ofvmy laminated wall. f

Referring to Figs. 6, 7 and 8, I have therein shown diagranimatically a laminated sheet metal wall built up o two'la'ers 1, 2, of thin sheet metal highly magni ed and bent into the forni of a corrugation. Each sheet 1 and 2 is represented as composed of smallv sections 3, 3', 4, 4', of white squares and hatched squares respectively. InV Fi 6 the corrugated wall is assumed to be in its normal position, while in Fig. 7 ythe wall is shown as collapsed below its normal position, and in Fig. A7 it is expanded above its normal position. Compare the laminated Wall when in normal position, as shown in Fig. 6, and collapsed position, as in Fig. 7.v The corresponding sections 3, 3 and 4, 4', register with each other in normal position. Then the wall-is collapsed, as shown in Fig.

", the' layer 1 of metal on the ,convex side ofthe bends, or above the so-called median line, is placed under tension to separate its portions 3, 4, while the layer below the median line is placed under compression to contract its portions 3', 4. Since the layers of metal 1 and 2 are tree to glide over each other during the collapsingof the wall, the' sections 3, 3 and 4, 4', will shift their -positions past each other, as vindicated in Fig. 6. The sections at the apex and in the vicinity of the line A-B will not shift, or

-at least very little, with respect to each other, It will thus be observed that by lamliind ot' a seam. l prefer, however, to

inating the metal in the wall of the corrugation, the metal lof the wall above and below the so-called median line has greater freedom of movement, thereby relieving the layer l of some of its tendency to stretch, and of layer 2 to contract. The wall as a whole is more exible, because enabled to be collapsed and extended from its normal posir` tion with' less force than inl the case where the two layers fornra` homogeneous wall. vThe wall possesses greater strength because made up of layers of metal rolled into thin sheets having a proportionally greater tensile strength. In Fig. 8 the wall is show ii in its expanded position. while taking this position, the wall has been expanded above the normal position shown in Fig. G, and the layers 1 and 2 of the wall have been subjected to a reverse set of bending strains causing them to shift in the opposite direction to that when the wall is collapsed, as may be seen by considering the sections 3, 3 and l, l. The same freedom of movement of the layers ofanetal to glide past each other exists during the collapsing of the wall as during the period of expanding, and for the' same reasons as explained in considering Fig. 7. The movement, however, is in an opposite direction.

In Figs. and 2, I have shown a collapsible and expansible corrugated tubular wall 5 built up of four separate sheets or laniinzr G, 7, 8 and 9, of thin sheet metal such as brass, steel, copper or the like. Each sheet /has been bent up into tubular Aform and its edges united by a brazed lapped seam 6', 7', 8 and/9', as shown iii Fig. Q, and as de scribed and claimed in my application Serial No. 317,157, filed May 16th, 1906. The diameter ofeach tube i as been adjusted so that the tubes will lit or nest together.l The seams of the tubes are'preferably adjusted at equal angular distances, vandthe tube is then provided with corrugations of any desired form. By the proper distribution of the seams there is effected a balance of the slight inequalities in resilience between the wall at the seam and elsewhere. Yhile the wall is somewhat thickened at the lapped seam, this thickening by presence of the seam has been distributed ,around the wall, and is decidedly less at any one seam than at the lapped seam of a solid wall having the saine thickness elsewhere. l

The wall as thus constructed in laminze safe-guards against any accidental flaws or imperfections at the seams. lVhile a flaw` mightoccur in one seam, such defect would not detractseriously from the eiciency of the wall, because of the fact that` the remaining seams would prevent all possibility The laminated walls here illustrated are shown as inagniiied for the purpose of better illustration. A thickness of .01 inch for my laminated Wall.

` A collapsible and expansible wall as thus constructed of laminae possesses greater flexibility than a similar wall made of solid sheet metal and of the same thickness, for the reasons above explained in connection with the diagrams Figs. 6, 7 and 8, and also has greater capability for withstanding heavy pressures of fluids confined thereby,

' as also above explained.

ln Fig. 3 is shown, in highly magnified form, a portion of a laminated wall having between its layers a lubricating material l0, such as graphite, the advantage of which is to facilitate the adjustment olj the layers in the wall during collapsing and expanding of the same.

Instead of constructing the laminated wall of independent sheets of metal, as shown in Figs. 1 and 2, l may employ a sin gle sheet ot metal coiled in the manner shown in Figs. 4 and 5 to form a plurality of layers, and braze bothiedges ll, l2, t0,

thel wall, or only braze the outer edge, leaving the inner edge to be held'by the configuration of the wall. The edges 1l, l2',

lmay overlap each other as shown in Fig. 4,

or they may terminate without overlapping, as illustrated in Fi 5, and then be pressed flush with the sur acesof the wall. This may be done in the brazing operation.` l prefer, however, the construction shown in Figs. 1 and 2, wherein a plurality of independent sheets are employed which afford opportunity of using metals of dierent kinds in the several layers, and thereby util izing in combination the desirable properties of the different metals, such as combining the use of a metal like copper, which resists corrosion of steam, and that of steel, whlilch lends strength and elasticity to the Wa What' l claim is p l. A collapsible and extensible corrugated wall composed of superimposed layers of Sheet metal. 2. A collapsible and extensible corrugated tubular wall composed of superimposed layers of sheet metal.

3. A collapsible and extensible corrugated tubular wall composed of superimposed layers of sheet metal and lubricating material between the layers.

d. A collapsible and extensible corrugated tubular wall composed of superimposed layers of sheet metal one of which layers diders from the other in its chemical properties.

5; A dexible corrugated wall composed of a plurality of thin layers having' a i'ilm of lubricant between said layers.

6. A tubular laminated metal wall capable of being expanded and collapsed in the direction of its axis and having a iilm of lubricant between the laminations.

7. A flexible corrugated tubular metal wall composed of a plurality of thin layers having longitudinally disposed lap seams.

8. A flexible corrugated tubular metal wall composed or va plurality of th'in layers having longitudinally disposed lap seams, no two of which seams coincide.

9. A exible corrugated tubular metal wall composed of a plurality of thin layers having longitudinally disposed lap arranged at approximately equal intervals around the circumference of the wall.

ln testimony whereof l have signed this specification in the presence of two subscribing witnesses,

WESTON M. FULTN.

I Vllitnessee: A Y

MARGARET Cocinas, E. d. S. HYATT.

seams', 

